The master cyl. will look perfectly dry from the outside, looking behind the driver's side wheel. The fluid leaks out of the rear of the MC, in the bulkhead area. You might want to try removing the carpet, floor mat, etc. where the pedals are, and you will get a better idea how the MC can leak and then fluid drips from the front or rear holes in the spine, coz it's difficult to explain.
So, it sounds like you need a new MC, which will need to be bench-bled prior to install. You should get a bentley manual ($30+/-), available from just about all the mail order places, maybe even amazon. the 2nd "economy" option is the haynes manual, which is under $20 and is available in borders, barnes/noble, pep boys, etc. in stock. Either of these books will also have factory shots of the floor pan/bulkhead area where the MC bolts in, and you will get a better idea of how the fluid leaks undetected, etc.
You will also need to rinse out the spine & bulkhead area w/ alcohol, lacquer thinner, or acetone to remove the brake fluid residue and then coat with some kind of paint to prevent rust. I used rustoleum primer that was thinned down and it seems to have worked pretty well.
=================================
" ..... I ain't no bandleader!!"